Offline Files helps you be more productive. You can use this feature on a portable computer, or on a desktop computer that occasionally connects to your workplace network. For example, this feature is useful if you are working at home on a desktop computer, and need to automatically get files off the network whenever you connect.
The files that you select are automatically downloaded from shared folders on the network and stored on your computer. When you disconnect, the files are available to use. When you reconnect to the network, your changes are added to the files on the network in a process called synchronization. If someone else on the network made changes to the same file, you can save your version, keep the other version, or save both.
For more information on using offline files, see Microsoft Support.